We begin our study of the **Gemara** in **Shabbat** on folio 37a. This study of **Masechet** **Shabbat** is dedicated by **Benjamin Stavsky** for a complete recovery for all the sick of **Israel**. Our current discussion seeks to clarify the intent of the **Mishnah** found at the beginning of the **Perek** titled **Kirah**. The central question is whether that **Mishnah** follows the opinion of the Sages, who require an oven to be swept of its coals or covered with ash before one may leave food on it to stay for the Sabbath, or if it follows the view of **Chananya**. According to **Chananya**, one may leave food on an unswept oven as long as it was partially cooked—to the extent of the food of Ben Drosai—before the Sabbath began. In his view, the requirement for an oven to be swept or covered only applies to returning food to the fire on the Sabbath itself, not to leaving it there from Friday afternoon.
To resolve this, the **Gemara** analyzes a tradition cited by **Rabbi Helbo** in the name of **Rav Hama bar Guria** and **Rav**. This tradition states that the permission granted to keep food on an oven applies only to placing it on top of the oven, where the heat is less intense, but placing it inside the oven is forbidden. The **Gemara** suggests that if the **Mishnah** is discussing the laws of returning food on the Sabbath, while leaving food there from Friday is generally permitted even on an unswept oven, then the distinction between the top and the inside of the oven is logical. Inside the oven, the heat is much greater, and according to **Rashi**, this would constitute a forbidden form of insulation that adds heat. However, if the **Mishnah** is interpreted as requiring the oven to be swept or covered even for leaving food there from Friday, then the distinction disappears. If the coals are already removed or covered, there should be no difference between placing the pot on top or inside.
The **Gemara** counters this by suggesting that **Rabbi Helbo** was not referring to the first section of the **Mishnah** but rather to the latter section. In that section, **Bet Hillel** permits returning food to an oven that has been swept or covered. **Rabbi Helbo** clarifies that even according to **Bet Hillel**, this permission only applies to the top of the oven. Placing it inside remains forbidden because it appears too much like the act of cooking. Thus, the distinction between the top and the inside does not necessarily prove which opinion the **Mishnah** follows regarding leaving food on the fire from Friday.
The **Gemara** then brings a proof from a **Braita** concerning two ovens that share a common wall. In this case, one oven is swept or covered, and the other is not. The law states that one may leave food on the swept oven even though heat from the adjacent unswept oven reaches it. The **Braita** then records a dispute: **Bet Shammai** says nothing may be left on it, while **Bet Hillel** says hot water may be left, but not cooked food. This is the version of **Rabbi Meir**. However, **Rabbi Yehuda** provides a different version where **Bet Shammai** allows hot water but not cooked food, and **Bet Hillel** allows both. **Rabbi Yehuda** also notes that **Bet Hillel** allows returning the food to the oven, while **Bet Shammai** does not. The **Gemara** observes that if our **Mishnah** is about leaving food on the fire, it aligns perfectly with **Rabbi Yehuda**. But if the **Mishnah** is about returning food, it fits neither **Rabbi Meir** nor **Rabbi Yehuda**, as their dispute centered on an oven that was already swept or covered.
A new inquiry is raised: Is it permissible to lean a pot against the outside wall of an unswept oven? One might argue that while the top and inside are forbidden, the outside is permitted. The **Gemara** attempts to find an answer in the case of the two ovens sharing a wall. It suggests that since one may leave food on the swept oven despite the heat from the unswept neighbor, leaning should be permitted. However, this is rejected because air circulates between the two ovens, whereas leaning a pot directly against a wall is different. A teaching from **Rav Safra** in the name of **Rav Hiya** is then cited, stating that if an oven was covered with ash but the fire rekindled, one may still lean a pot against it or leave food on top. This implies that if it had never been covered, leaning would be forbidden. The **Gemara** eventually concludes with a clear ruling from another source: one may lean a pot against an oven fueled with materials that produce coals, but one may only leave food on top if the oven is swept or covered.
The discussion shifts to the specific status of food that is fully cooked. **Rabbi Yitzchak bar Nachmani** quotes **Rabbi Oshaya**, stating that if an oven was covered with ash but then rekindled, one may leave hot water or food on it, provided they are fully cooked. This suggests that even if the food improves by being left on the heat, it is permitted because the initial act of covering the coals demonstrates that the owner is not interested in stoking the fire. The **Gemara** notes that this is a novel point; one might have thought that once the fire rekindles, the oven returns to its forbidden, unswept status. **Rabbi Oshaya** teaches that it retains a middle status where fully cooked food is permitted.
The **Gemara** then presents three versions of the opinion of **Rabbi Yochanan**. The first, cited by **Rabba bar bar Chana**, aligns with the Sages: staying food on an unswept oven is forbidden, but if it was covered and rekindled, fully cooked food is allowed even if the heat improves it. The second version, cited by **Rav Sheshet**, aligns with **Chananya**: leaving food on the fire from Friday is permitted even on an unswept oven as long as it is partially cooked, and the requirement to sweep or cover the coals applies only to returning food on the Sabbath. **Rav Sheshet** supports this by pointing to a **Mishnah** on folio 19, which permits leaving bread in an oven as long as its surface has crusted over. The third version, cited by **Rav Shmuel bar Yehuda**, suggests that even the Sages would allow leaving fully cooked food on an unswept oven, even if the heat improves it; they only forbade leaving food that was only partially cooked.
When **Rav Shmuel bar Yehuda** shared this, other scholars challenged him, noting that **Rav** and **Shmuel** both ruled that if heat improves the food, it is forbidden to leave it on an unswept oven. He responded that he was specifically quoting the view of **Rabbi Yochanan**, regardless of other opinions. **Rav Ukva** from **Mishan** later told **Rav Ashi** that since the people of **Bavel** live near the influence of **Rav** and **Shmuel**, they should follow their stricter ruling.
Finally, the **Gemara** looks at practical applications. **Abaye** asked **Rav Yosef** about the law, and **Rav Yosef** pointed out that **Rav Yehuda** would leave food on an unswept oven and eat it. This was dismissed because **Rav Yehuda** was dangerously ill, and the laws are relaxed for such a person. However, it was noted that in the city of **Sura**, they followed the lenient view, and **Rav Nachman bar Yitzchak**, who was very meticulous, would leave food on an unswept oven. **Rav Ashi** recalled seeing **Rav Huna** leave a specific fish dish on an unswept flame. He was unsure if **Rav Huna** did this because he held that food which improves with heat is permitted, or because the flour in that dish actually caused it to deteriorate with more heat, which everyone permits.
**Rav Nachman** provides a final set of rules: food that improves with heat is forbidden on an unswept oven, while food that deteriorates is permitted. Generally, any dish containing flour deteriorates with heat, except for a turnip dish containing meat, which improves. However, if that turnip dish is being prepared for guests, it is considered to deteriorate because the meat shrivels, making it unpresentable. Dishes made of farina, dates, or figs also deteriorate with prolonged heat. **Rashi** concludes by noting that the common practice follows **Chananya**. We rely on the ruling that as long as food is partially cooked, it may be left on an unswept oven before the Sabbath. This is because the **Mishnah** regarding bread crusting over serves as a standard, and we interpret the requirement for sweeping or covering as applying only to returning food on the Sabbath itself.